#smoking pregnancy /smoking Pregnant /animated 4 f/s run 1, 10 sec delay Smoking during pregnancy passes nicotine & carbon monoxide into the baby's {bloodstream}. Nicotine makes the baby's heart beat too fast. Carbon monoxide means that less {oxygen} & nutrients reach the baby. A {still birth} is more likely & a higher risk of a premature or underweight baby. Physical & mental development of children of mothers who smoke during pregnancy can be affected.